RUNX1 Do you have any info?

I am cross posting this from the newly diagnosed board, as I'm new and not sure who frequents what boards and really want info!

Brand new to the group...first post, and glad to find you!

My husband (and one of his brothers) had "the tendency to bleed" as children. He was told he grew out of it, but his brother never did. His platelet count was within but at the low end of normal for many yr (he is 41). On a recent preoperative appt for an unrelated surgery, his platelet count was in the 50K's. We insisted on seeing a hematologist to get to the source of the issue. After many tests, he was told he has ITP-immune thrombocytopenia purpura. They did another test that was a genetic test to determine if he has the gene mutation that correlates higher incidence of familial thrombocytopenia developing leukemia. Well, the test was positive.

I know that the positive test result doesn't mean he will get leukemia, but that there is a higher incidence.

What can you tell me about this RUNX1?

They said we need to have our 10 month old tested. UGH!

other pertinent info: His brother, whom has always been much more symptomatic, has a 12 yr old daughter that is also highly symptomatic. She required transfusion and emergent care when she began her menstrual cycle. They didn't test her, evidently, for diagnosis, only administering hormone therapy to minimize bleeding.

I have read that the RUNX1 mutation has only been identified in approximately 20 families as of a few years ago.

If you have any information, please, please share!!
Thank you!
I look forward to learning from your experiences!